*4.2. Empty Pea Pods Extract (EPPE)*

Following the method outlined by Pinchao-Pinchao et al. [55], ultrasonic-assisted extraction (Elmasonic, Singen, Germany) was used to extract polyphenol components from powdered EPP. The best conditions (30 ◦C, 20 min, 50% ethanol concentration, and a liquid solid ratio of 1:40) were utilized to prepare EPPE with ethanol as the solvent. The extracted material was wrapped in aluminium foil and kept at −18 ◦C. Under the influence of a nitrogen gas stream, the solvent was eliminated.
